Viscose composition and regenerated cellulose bands



United States Patent VISCOSE COMPOSITION AND REGENERATED CELLULOSE BANDSWilliam Grogan OConnell, Buffalo, N. Y., assignor to E. I. du Pont deNemours and Company, Wilmington, Del., a corporation of Delaware N0Drawing. Application September 28, 1951, Serial No. 248,885

8 Claims. (Cl. 106-164) This invention relates to shrinkable secondarycontainer closures for rendering bottles, jars, etc. attractive andtamper-resistant. More particularly, this invention relates toshrinkable secondary container closures having the appearance of metalfoil.

Heretofore, it has been customary to enclose the upper part of the neckand the primary closure of bottles of many types of alcoholic liquors,particularly wines, in a thin, decorative metal capsule or a wrapping ofmetal foil. This practice has also been adopted for a great deal of thebottled non-alcoholic beverages for the primary purpose of sales appeal.However, the metal foil secondary closure has many disadvantages, suchas poor fit, which detracts from the appearance, lack of adhesion, whichallows it to slip oflf the bottle neck before the time of willfulremoval, etc. To overcome these disadvantages, it has been proposed tosubstitute for the metal foil, shrinkable, nonfibrous bands ofregenerated cellulose.

Shrinkable, non-fibrous secondary closures, i. e., bands and caps, ofregenerated cellulose, have been known and used extensively for a numberof years. They provide an attractive decoration for the container, adeterrent against tampering with the contents thereof, and, whenpigmented, an effective background for printing advertising matter.

To seal and/or decorate a bottle, the shrinkable band in gel form isplaced over the bottle top (the primary closure, such as a stopper orcap, being in place) and allowed to dry. The evaporation of the waterfrom the band causes it to shrink and fit very firmly around the bottleneck and primary closure to form an attractive,

tightly-stretched, tough seal. Although this type of secondary closuremay be produced by various procedures, the great bulk of present-dayproduction is manufactured by cutting short sections from continuouslengths of cellulose tubing regenerated from viscose. The manufacture ofregenerated cellulose tubing from viscose and its subsequent cuttinginto short lengths (bands) is described by Webster in U. S. P.1,647,489, by Vautier and Fays in U. S. P. 2,141,776, and by Dalton inU. S. P. 2,161,561.

An object of this invention is to provide a viscose compositioncontaining wet-ground, heat treated mica and a shrinkable secondaryclosure of regenerated cellulose which closely resembles metal foil inappearance made therefrom, but which retains all of the advantagesinherent in regenerated cellulose shrinkable secondary closures. Morespecific objects are to provide bands of regenerated cellulose havingthe appearance of gold, and to provide bands of regenerated cellulosehaving the appearance of silver. These and other objects will moreclearly appear hereinafter.

The objects hereinabove stated are accomplished by the present inventionwhich, briefly stated, comprises incorporating in viscose from which theregenerated cellulose secondary closure is to be formed, from 20 to 65%by weight of finely-divided, heat-treated mica; from 0 to 4% ofstainless steel flake; and from 0 to 12% of coloring agent, all based onthe weight of the cellulose in the viscose, converting the viscose togel regenerated cellulose structures of the desired shape, andimpregnating the regenerated cellulose shaped structure with an aqueoussoftener bath containing not more than 10% softener consisting of 3.5 to8% glycerol and from 0 to 5.0% urea, the ratio of glycerol to urea beingnot less than 1.6 to 1.

By heat-treated mica is meant mica, preferably Wetground, which has beenheated at the temperature at which the pieces or particles adheretogether slightly to form a loosely-held, porous cake which can bebroken into small chunks by hand.

It is known to heat-treat transparent mica to produce an opaque productof enhanced light reflectivity by heating the natural transparent mica(which contains water tightly bound in the crystal lattice structurethereof) to the temperature at which the mica pieces or particles caketogether slightly. The temperature at which this occurs will, of course,be difierent for each type of mica. Thus, muscovite, which is the mostreadily available type of mica, cakes together loosely when heated at atemperature of 17l0il0 F. for 12 hours, or at 1875 F. for ten minutes.All types of mica are susceptible to this heattreatment; and all typesof mica with a laminar structure, except those which have a high ironcontent, are suitable for purposes of this invention. Suitable typesinclude, in addition to muscovite, phlogopite and sericite. A high ironcontent, such as is found in biotite, causes the mica to turn dark onheating and, in most instances, renders it unsatisfactory for use inbands, caps, etc.

To obtain satisfactory opacity and reflectivity, the mica must bewet-ground either before or after heat-treatment, preferably in slurryform in a ball or pebble mill. Other wet-grinding procedures such asthose used in the mica industry can also be used. Wet-grinding insuresthat the mica particles will be in the form of platelets which tendtoward planar orientation in the extruded band. When wet-grinding isperformed before the heat-treatment, the loosely-held, porous cake ofheat-treated mica may be broken down into the requisite platelet formand particles size by either wetor dry-grinding.

Preferably, the size of the heat-treated mica particles (i. e.,platelets) should be such that at least of the particels are between 20and microns measured in their longest dimension. Particle sizes above100 microns cause low opacity coverage per unit of mica weight, andsizes below 20 microns tend to dull off the band luster. From 20% to 65%mica is used, based on the weight of the cellulose in the viscose.Heat-treated, wet-ground micas are preferred to dry-ground micas.

The absolute opacity of the bands of this invention is improved by theaddition of opacifiers such as barium chloride, barium titanate,titanium dioxide, stainless steel flake, etc. A small amount ofstainless steel flake adds both to the opacity and to the luster. From0% to 4% stainless steel flake may be used and/or from 0% to 10% ofother opacifiers, based on the cellulose content of the viscose. Bandshaving a beautiful silver-like appearance may be made from viscosecontaining 40% heat-treated, Wet-ground mica and 0.5 to 2% stainlesssteel flake. The flake is made from a standard stainless steel alloycontaining from 17% to 28% by weight of chromium and from 8% to 16% byweight of nickel, based on the Weight of the alloy, with the flake beingof such a particle size that substantially all of the flake will passthrough a 140 mesh screen and at least 55% of the flake will passthrough a 325 mesh screen. A 140 mesh screen has a square screen openingof microns; a 325 mesh screen has a square screen opening of 44 microns.

Bands not containing opacifiers in addition to the heattreated mica, insome instances, exhibit a pronounced translucency, especially in thecase of bands on brown bottles. The lack of apparent opacity of suchbands is caused by a film of softener making an unbroken interfacebetween the band and the bottle. This detrimental translucent effect canbe eliminated by using a specific softener combination comprising 3.5%to 8% glycerol (solution concentration) with the various usualpreservatives, and from to urea, the total concentration of softenerbath not exceeding and the ratio of glycerol to urea being not less than1.6 to 1.0.

The examples set forth in the following table further illustrate thepractice of this invention. The coloring agents are identified by theiromcial Color Index numbers as given in Rowes Color index1924, or by thenumbers 4. Regenerated cellulose secondary band closures for bottles andthe like containing to 65% by weight, based on the weight of cellulose,of particles of Wetground heat-treated mica, 80% of said particlesmeasuring between 20 and 100 microns, and up to 4% by weight ofstainless steel flake, said bands having been softened in a softenerbath containing not over 10% softener consisting of from 3.5% to 8% ofglycerol and up to 5.0% of urea, the ratio of glycerol to urea being notless than 1.6 to 1.

5. Gel regenerated cellulose shrinkable bands pigmented with from 20% to65% by weight, based on the weight of cellulose, of silvery-whiteparticles of wetof the patents which cover them. Parts are by weight un-1;) ground, heat-treated mica, 80% of said particles measurlessotherwise stated: ing between 20 and 100 microns, and up to 4% by weightPercent Ingeeglligfitsseigglitsggtse Based on Finished Dried BandColoring Ex Ar ent H. '1. Stainless e Percent W. G.* Steel AbsoluteMica, Flake Other Opaeifier Luster Color Opacity Percent Percent 40 2.4%Barium Chloride". Fair to Good. G0ld Good.

40 1.0 do Excellent -do... Do.

40 do 7 }Good do Do.

Excellent Do.

40 1.0 3.0% Barium Titanate. Good to Excellent.

Wet-ground mica (Muscovite) heat-treated at 1710i10 F. for 12 hour (A)Example 10 of U. S. P. 2,559,669 to Schroeder et al.

(B) Color Index Number 1132. I

(0) Example 1 of U. S. P. 1,090,621 to Isler.

(D) Color Index Number 1120.

(E) Example 2 of U. S. 1. 1,988,205 to Kunz et :11.

(F) Color Index Number 1006.

(G) Example 1 01 U. S. P. 1,667,848 to Gassner.

The viscoses of this invention illustrated in the foregoing examples maybe used in making any of the various known types of bands. Thus, theymay be used to make solid opaque bands or bands with opposed transparentstripes such as the window type band of Vautier and Pays in UnitedStates Patent No. 2,141,776. They may be used as an outer layer in bandssimilar to those described in Half et al., United States Patent No.2,331,974. They may also be used as an underlayer in making bandssimilar to those described by Czapek in United States Patent No.1,918,383.

I claim:

1. An ornamental regenerated cellulose pellicular structure comprisedessentially of regenerated cellulose pigmented with from 20% to 65% byweight, based on the weight of cellulose, of particles of wet-groundheattreated mica, 80% of said particles measuring between 20 and 100microns, and up to 4% by weight of stainless steel flake.

2. Regenerated cellulose secondary band closures having the appearanceof gold, containing 40% by weight, based on the weight of cellulose, ofparticles of Wetground heat-treated mica, 80% of said particlesmeasuring between 20 and 100 microns, 2% stainless steel flake, 35

and 3% to 10% of a yellow vat dye.

3. Regenerated cellulose secondary band closures having the appearanceof silver, containing 40% by weight, based on the weight of cellulose,of particles of wetground, heat-treated mica, 80% of said particlesmeasuring between 20 and 100 microns, and from 0.5% to 2% of stainlesssteel flake of such particle size that substantially all of the flakewill pass through a 140 mesh screen and at least 55% of the flake willpass through a 325 mesh screen.

of stainless steel flake and impregnated with a softener bath containingfrom 3.5% to 10% of glycerol.

6. Viscose containing from 20% to 65% by weight, based on the weight ofcellulose in the viscose, of particles of wet-ground, heat-treated mica,of said particles measuring between 20 and microns, and up to 4% byweight of stainless steel flake.

7. Viscose containing 40% by Weight, based on the weight of cellulose inthe viscose, of particles of wetground, heat-treated mica, 80% of saidparticles measuring between 20 and 100 microns, and from 0.5% to 2% ofstainless steel flake of such particle size that substantially all ofthe flake will pass through a mesh screen and at least 55% of the flakewill pass through a 325 mesh screen.

8. Viscose containing 40% by weight, based on the weight of cellulose,of particles of wet-ground, heat treated mica, 80% of said particlesmeasuring between 20 and 100 microns, 2% stainless steel flake, and 3%to 10% of a yellow vat dye.

References Cited in the file of this patent UNITED STATES PATENTS109,416 Johnston et a1. Nov. 22, 1870 1,045,990 Lindsay Dec. 3, 19122,013,739 Wright Sept. 10, 1935 2,204,063 Atwood June 11, 1940 2,307,760Creadlick Jan. 12, 1943 FOREIGN PATENTS 983,563 France Tune 25, 195112,543 Australia a of 1933 244,540 Switzerland Apr. 16, 1947

6. VISCOSE CONTAINING FROM 20% TO 65% BY WEIGHT, BASED ON THE WEIGHT OFCELLULOSE IN THE VISCOSE, OF PARTICLES OF WET-GROUND, HEAT-TREATED MICA,80% OF SAID PARTICLES MEASURING BETWEEN 20 AND 100 MICRONS, AND UP TO 4%BY WEIGHT OF STAINLESS STEEL FLAKE.